3 条题解

  • 1
    @ 2026-4-1 13:03:23
    
    ```#include<bits/stdc++.h>
    using namespace std;
    int n,k,v,x[10000005];
    int erfen(int n,int k){
        int l=1,r=n,s=-1;
        while(l<=r){
            int mid=(l+r)/2;
            if(x[mid]==k){
                r=mid-1;s=mid;
            }else if(x[mid]<k){
                l=mid+1;
            }else{
                r=mid-1;
            }
        }
        return s;
    }
    int main(){
        scanf("%d",&n);
    
        int y;scanf("%d",&y);
        for(int i=1;i<=n;i++)scanf("%d",&x[i]);
        if(erfen(n,y)!=-1)printf("YES\n");
        else printf("NO\n");
        return 0;
    }
    • 0
      @ 2026-4-7 21:36:53
      using namespace std;
      int n,k,v,x[10000005];
      int erfen(int n,int k){
          int l=1,r=n,s=-1;
          while(l<=r){
              int mid=(l+r)/2;
              if(x[mid]==k){
                  r=mid-1;s=mid;
              }else if(x[mid]<k){
                  l=mid+1;
              }else{
                  r=mid-1;
              }
          }
          return s;
      }
      int main(){
          scanf("%d",&n);
      
          int y;scanf("%d",&y);
          for(int i=1;i<=n;i++)scanf("%d",&x[i]);
          if(erfen(n,y)!=-1)printf("YES\n");
          else printf("NO\n");
          return 0;
      }
      • 0
        @ 2026-4-7 13:26:03

        #include using namespace std; int main() { int n,x,i,f=0; cin>>n>>x; int a[200005]; for(i=0;i<n;i++)cin>>a[i]; for(i=0;i<n;i++)if(a[i]==x)f=1; if(f)cout<<"YES"; else cout<<"NO"; return 0; }

        • 1

        二分查找-类型1(查找某个数字是否出现过)

        信息

        ID
        4939
        时间
        1000ms
        内存
        128MiB
        难度
        2
        标签
        递交数
        81
        已通过
        34
        上传者